Motor vehicles such as automobiles and trucks are becoming increasingly technologically sophisticated requiring a correspondingly more sophisticated set of test equipment for maintenance and diagnostic testing. Much of the increased complexity of motor vehicles is due in part to the increased complexity of electrical circuitry and systems incorporated therein. Troubleshooting and diagnosing problems with such electrical systems requires the use of a wide array of complex test equipment.
Such test equipment may include, for example, devices commonly referred to as multi-meters that are configured to measure various electrical parameters, such as resistance, voltage, current, and the like. Other diagnostic testing that is typically performed on motor vehicle electrical systems includes logic probes which measure and detect the presence and polarity of voltages, as well as determining continuity in electrical circuits.
One drawback, however, is that conventional logic probes typically are incapable of measuring specific voltage levels. Another drawback associated with prior art test equipment regards an inability to test electrical systems in a powered state. More specifically, many conventional multi-meters and logic probes are incapable of placing circuitry into an operational mode for the purpose of diagnosing problems with the circuitry. For example, certain electrical devices in an electrical system of an automobile having a non-operational engine cannot be tested in the normal operating mode. It will be appreciated, however, that it is desirable to test such devices in the operational mode in order to ascertain specific problems that can only be diagnosed when such devices are operating. For instance, a fan motor of a motor vehicle may require that the engine of the vehicle is operating in order to provide current to the fan motor. Unfortunately, unless power is provided to the fan motor by way of a separate power source, it is impossible to test and diagnose certain problems with the fan motor.
It will be appreciated that there exists a need in the art for a diagnostic circuit test device that is capable of providing power to an electrical system in order to test electrical systems in an active or powered state. Furthermore, there exists a need in the art for a diagnostic circuit test device that combines other test features, such as logic probe diagnostic testing, into a single unit. In addition, there exists a need in the art for a diagnostic circuit test device capable of combining key measurement functions into a single instrument in order to the accelerate diagnosis of electrical problems. Finally, there exists a need in the art for a diagnostic circuit test device that is hand held, and that is easy to use and which contains a minimal number of parts and is of low cost.